Dual check valve fluid circulation system for dishwasher appliances

ABSTRACT

A fluid circulation assembly for a dishwasher appliance includes a pump, a diverter, and a valve. The diverter includes an inlet and a plurality of outlet ports. The inlet of the diverter is in fluid communication with the pump for receiving fluid from the pump. The valve is in fluid communication with the diverter via one or more of the plurality of outlet ports. The valve includes a housing, a dual check valve assembly mounted in the housing and a plurality of conduits. The dual check valve assembly selectively directs fluid from the diverter to one or more of the plurality of conduits.

FIELD

The subject matter of the present disclosure relates generally todishwasher appliances, and more particularly to fluid circulationsystems within dishwasher appliances.

BACKGROUND

Dishwasher appliances generally include a tub that defines a washcompartment. Rack assemblies can be mounted within the wash chamber ofthe tub for receipt of articles for washing. Spray assemblies within thewash chamber can apply or direct wash fluid towards articles disposedwithin the rack assemblies in order to clean such articles. Multiplespray assemblies can be provided including e.g., a lower spray armassembly mounted to the tub at a bottom of the wash chamber, a mid-levelspray arm assembly mounted to one of the rack assemblies, and/or anupper spray assembly mounted to the tub at a top of the wash chamber.

Dishwasher appliances further typically include a fluid circulationsystem which is in fluid communication with the spray assemblies forcirculating fluid to the spray assemblies. Such fluid circulationsystems typically include at least one pump for circulating fluidthrough the multiple spray assemblies. In addition, a device, referredto as a diverter, may be used to control the flow of fluid received fromthe pump. For example, the diverter can be used to selectively controlwhich spray assemblies receive a flow of fluid. In one construction, thediverter uses an electrically powered motor to rotate a valve betweendifferent ports for fluid control. Another construction uses ahydraulically actuated rotation mechanism to position a diverter valveto provide the desired fluid flow between spray assemblies without theneed for a motor.

The diverter is a significant tool for complying with governmentregulations related to total energy and water usage for a dishwashercycle. For example, a dishwasher may use a diverter to run only onespray assembly at a time, thereby decreasing the amount of waterrequired to run a cycle compared to a dishwasher that runs all sprayassemblies at the same time. Therefore, a dishwasher with a diverter maybe more capable of meeting government regulations than a dishwasherwithout a diverter. However, because only one rack is being washed at atime, the total cycle time must increase so that the total wash time foreach rack and the overall wash performance may be maintained. Althoughdiverters are useful in meeting governmental regulations, conventionaldiverters typically provide little versatility to a user in selectingdifferent flow combinations, which can increase cycle times and lead toa poor consumer perception of the washing machine appliance.

Accordingly, a dishwashing appliance that can be configured toselectively control the flow of fluid through one or more differentspray assemblies or other fluid elements would be useful. Moreparticularly, a diverter for a dishwasher appliance providing reliable,versatile, and useful flow combinations to a plurality of sprayassemblies using variable flows paths and rates would be especiallybeneficial.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In an aspect of the present disclosure, a dishwasher appliance isprovided. The dishwasher appliance defines a vertical direction, alateral direction, and a transverse direction that are mutuallyperpendicular. The dishwasher appliance includes a tub defining a washchamber for receipt of articles for washing. A lower spray assembly islocated in the wash chamber and configured to direct a spray of fluidinto the wash chamber. An upper spray assembly is located in the washchamber above the lower spray assembly along the vertical direction. Theupper spray assembly is configured to direct a spray of fluid into thewash chamber. A sump is positioned at a bottom of the wash chamber forreceiving fluid from the wash chamber. The dishwasher appliance alsoincludes a fluid circulation assembly disposed within the sump. Thefluid circulation assembly includes a pump in fluid communication withthe sump. The pump is configured to draw fluid from the sump. The fluidcirculation assembly also includes a diverter comprising an inlet influid communication with the pump for receiving fluid from the pump anda plurality of outlet ports. The fluid circulation assembly furtherincludes a valve in fluid communication with the diverter via one ormore of the plurality of outlet ports. The valve includes a housing, adual check valve assembly mounted in the housing, and a plurality ofconduits. The dual check valve assembly is configured to selectivelydirect fluid from the diverter to one or more of the plurality ofconduits.

In another aspect of the present disclosure, a fluid circulationassembly is provided. The fluid circulation assembly includes a pump, adiverter, and a valve. The diverter includes an inlet and a plurality ofoutlet ports. The inlet of the diverter is in fluid communication withthe pump for receiving fluid from the pump. The valve is in fluidcommunication with the diverter via one or more of the plurality ofoutlet ports. The valve includes a housing, a dual check valve assemblymounted in the housing and a plurality of conduits. The dual check valveassembly selectively directs fluid from the diverter to one or more ofthe plurality of conduits.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures.

FIG. 1 provides a front view of a dishwasher appliance which may includeembodiments of the present disclosure.

FIG. 2 provides a section view of the dishwasher appliance of FIG. 1.

FIG. 3 provides a section view of a fluid circulation assembly accordingto embodiments of the present disclosure.

FIG. 4 provides a perspective view of a portion of the fluid circulationassembly of FIG. 3.

FIG. 5 provides a perspective view of internal components of the portionof the fluid circulation assembly of FIG. 4.

FIG. 6 provides a bottom view of the internal components of FIG. 5 witha dual check valve in a first position.

FIG. 7 provides a bottom view of the internal components of FIG. 5 withthe dual check valve in a second position.

FIG. 8 provides a bottom view of the internal components of FIG. 5 withthe dual check valve in a third position.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

As used herein, the term “article” may refer to, but need not be limitedto dishes, pots, pans, silverware, and other cooking utensils and itemsthat can be cleaned in a dishwashing appliance. The term “wash cycle” isintended to refer to one or more periods of time during which adishwashing appliance operates while containing the articles to bewashed and uses a detergent and water, preferably with agitation, to,e.g., remove soil particles including food and other undesirableelements from the articles. The term “rinse cycle” is intended to referto one or more periods of time during which the dishwashing applianceoperates to remove residual soil, detergents, and other undesirableelements that were retained by the articles after completion of the washcycle. The term “wash fluid” refers to a liquid used for washing and/orrinsing the articles and is typically made up of water that may includeother additives such as detergent or other treatments.

FIGS. 1 and 2 depict an exemplary domestic dishwasher or dishwashingappliance 100 that may be configured in accordance with aspects of thepresent disclosure. For the particular embodiment of FIGS. 1 and 2, thedishwasher 100 includes a cabinet 102 having a tub 104 therein thatdefines a wash chamber 106. As shown in FIG. 2, the tub extends betweena top 107 and a bottom 108 along a vertical direction V, between a firstside and a second side along a lateral direction L, and between a frontside 111 and a rear side 112 along a transverse direction T. Each of thevertical direction V, lateral direction L, and transverse direction Tare mutually perpendicular to one another. The tub 104 includes a frontopening (not shown) and a door 114 hinged at its bottom 116 for movementbetween a normally closed vertical position (shown in FIGS. 1 and 2),wherein the wash chamber 106 is sealed shut for washing operation, and ahorizontal open position for loading and unloading of articles from thedishwasher 100. Latch 118 is used to lock and unlock door 114 for accessto wash chamber 106.

Upper and lower guide rails 120, 122 are mounted on the first and secondsides of tub 104 and accommodate roller-equipped rack assemblies 126 and128. Each of the rack assemblies 126, 128 is fabricated into latticestructures including a plurality of elongated members 130 (for clarityof illustration, not all elongated members making up assemblies 126 and128 are shown in FIG. 2). Each rack 126, 128 is adapted for movementbetween an extended loading position (not shown) in which the rack issubstantially positioned outside the wash chamber 106, and a retractedposition (shown in FIGS. 1 and 2) in which the rack is located insidethe wash chamber 106. This is facilitated by rollers 134 and 136, forexample, mounted onto racks 126 and 128, respectively. A silverwarebasket (not shown) may be removably attached to rack assembly 128 forplacement of silverware, utensils, and the like, that are otherwise toosmall to be accommodated by racks 126, 128.

The dishwasher 100 further includes a lower spray arm assembly 140 thatwill be described in more detail below. Lower spray arm assembly 140 maybe disposed in a lower region 142 of the wash chamber 106 and above atub sump portion 144 so as to rotate in relatively close proximity torack assembly 128. A mid-level spray arm assembly 146 is located in anupper region of the wash chamber 106 and may be located in closeproximity to upper rack 126. Additionally, an upper spray assembly 148may be located above the upper rack 126. As will be described in detailbelow, spray arm assemblies 140, 146, 148 may be part of a fluidcirculation assembly 150 for circulating water and dishwasher fluid inthe tub 104.

Each spray arm assembly 140, 146, 148 includes an arrangement ofdischarge ports or orifices for directing washing liquid received fromfluid circulation assembly 150 onto dishes or other articles located inrack assemblies 126 and 128. The arrangement of the discharge ports,also referred to as jets, apertures, or orifices, may provide arotational force by virtue of washing fluid flowing through thedischarge ports. Alternatively, spray arm assemblies 140, 146, 148 maybe motor-driven. The resultant movement of the spray arm assemblies 140,146, 148 provides coverage of dishes and other dishwasher contents witha washing spray. Other configurations of spray assemblies may be used aswell. For example, dishwasher 100 may have additional spray assembliesfor cleaning silverware, for scouring casserole dishes, for sprayingpots and pans, for cleaning bottles, etc. One skilled in the art willappreciate that the embodiments discussed herein are used for thepurpose of explanation only, and are not limitations of the presentsubject matter.

The dishwasher 100 is further equipped with a controller 156 to regulateoperation of the dishwasher 100. The controller 156 may include one ormore memory devices and one or more microprocessors, such as general orspecial purpose microprocessors operable to execute programminginstructions or micro-control code associated with a cleaning cycle. Thememory may represent random access memory such as DRAM, or read onlymemory such as ROM or FLASH. In one embodiment, the processor executesprogramming instructions stored in memory. The memory may be a separatecomponent from the processor or may be included onboard within theprocessor.

The controller 156 may be positioned in a variety of locationsthroughout dishwasher 100. In the illustrated embodiment, the controller156 may be located within a control panel area 158 of door 114 as shownin FIGS. 1 and 2. In such an embodiment, input/output (“I/O”) signalsmay be routed between the control system and various operationalcomponents of dishwasher 100 along wiring harnesses that may be routedthrough the bottom 116 of door 114. Typically, the controller 156includes a user interface panel/controls 160 through which a user mayselect various operational features and modes and monitor progress ofthe dishwasher 100. In one embodiment, the user interface 160 mayrepresent a general purpose I/O (“GPIO”) device or functional block. Inone embodiment, the user interface 160 may include input components,such as one or more of a variety of electrical, mechanical orelectro-mechanical input devices including rotary dials, push buttons,and touch pads. The user interface 160 may include a display component,such as a digital or analog display device designed to provideoperational feedback to a user. The user interface 160 may be incommunication with the controller 156 via one or more signal lines orshared communication busses.

It should be appreciated that the invention is not limited to anyparticular style, model, or configuration of dishwasher 100. Theexemplary embodiment depicted in FIGS. 1 and 2 is for illustrativepurposes only. For example, different locations may be provided for userinterface 160, different configurations may be provided for racks 126,128, different spray arm assemblies 140, 146, 148 may be used, and otherdifferences may be applied as well.

Referring now to FIG. 3, a fluid circulation assembly 150 according toan example embodiment of the present subject matter will be described.Fluid circulation assembly 150 may include a drive motor 170 that may bedisposed within sump portion 144 of tub 104 and may be configured torotate multiple components of dishwasher 100. As best shown in FIG. 3,drive motor 170 may be, for example, a brushless DC motor having astator 172, a rotor 174, and a drive shaft 176 attached to rotor 174. Acontroller or control board (not shown) may control the speed of motor170 and rotation of drive shaft 176 by selectively applying electriccurrent to stator 172 to cause rotor 174 and drive shaft 176 to rotate.Although drive motor 170 is illustrated herein as a brushless DC motor,it should be appreciated that any suitable motor may be used whileremaining within the scope of the present subject matter. For example,according to alternative embodiments, drive motor 170 may instead be asynchronous induction motor.

According to an exemplary embodiment, drive motor 170 and all itscomponents may be potted. In this manner, drive motor 170 may beshock-resistant, submersible, and generally more reliable. Notably,because drive motor 170 is mounted inside wash chamber 106 and iscompletely submersible, no seals are required and the likelihood ofleaks is reduced. In addition, because drive motor 170 is mounted in thenormally unused space between lower spray arm 140 and a bottom wall ofsump portion 144, instead of beneath the sump portion 144, this designis inherently more compact than conventional designs.

According to an exemplary embodiment, fluid circulation assembly 150 maybe vertically mounted within sump portion 144 of wash chamber 106. Moreparticularly, drive motor 170 of fluid circulation assembly 150 may bemounted such that drive shaft 176 is oriented along vertical direction V(FIG. 2) of dishwasher 100. So oriented, drive motor 170 may include atop side 180 facing top 107 of tub 104 and a bottom side 182 facing awayfrom the top 107 of tub 104.

As best shown in FIG. 3 and described below, rotatable drive shaft 176may extend out of both top side 180 and bottom side 182 of drive motor170. More particularly, a top portion 190 of drive shaft 176 may extendout of top side 180 of motor 170 toward top 107 of tub 104 and a bottomportion 192 of drive shaft 176 may extend out of bottom side 182 ofmotor 170 away from top 107 of tub 104. Notably, top portion 190 andbottom portion 192 may be part of the same, continuous, straight driveshaft 176 and thus rotate at the same speed.

Referring still to FIG. 3, drive shaft 176 is rotatably supported by anupper bearing 194 and a lower bearing 196. As illustrated, upper bearing194 is positioned at and operably coupled with top portion 190 of driveshaft 176 and lower bearing 196 is positioned at and operably coupledwith bottom portion 192 of drive shaft 176. As illustrated, bearings194, 196 are graphite sleeve bearings. However, it should be appreciatedthat any suitable bearing may be used while remaining within the scopeof the present subject matter. For example, bearings 194, 196 may be anysuitable combination of roller bearings, ball bearings, thrust bearings,bush bearings, etc.

As illustrated in FIG. 3, fluid circulation assembly 150 furtherincludes a filter 240. In general, filter 240 may define an unfilteredregion 242 and a filtered region 244 within sump portion 144. During awash or rinse cycle, wash fluid sprayed on dishes or other articleswithin wash chamber 106 falls into the unfiltered region 242. Wash fluidpasses through filter 240 which removes food particles, resulting inrelatively clean wash fluid within filtered region 244. As used herein,“food particles” refers to food soil, particles, sediment, or othercontaminants in the wash fluid which are not intended to travel throughfilter 240. Thus, a food particle seal may allow water or other washfluids to pass from the unfiltered region 242 to the filtered region 244while preventing food particles entrained within that wash fluid frompassing along with the wash fluid.

As illustrated, filter 240 is a fine mesh filter constructed from aperforated stainless steel plate. Filter 240 may include a plurality ofperforated holes, e.g., approximately 15/1000 of an inch in diameter,such that wash fluid may pass through filter 240, but food particlesentrained in the wash fluid do not pass through filter 240. However,according to alternative embodiments, filter 240 may be any structuresuitable for filtering food particles from wash fluid passing throughfilter 240. For example, filter 240 may be constructed from any suitablyrigid material, may be formed into any suitable shape, and may includeapertures of any suitable size for capturing particulates.

Still referring to FIG. 3, bottom portion 192 of drive shaft 176 isconfigured for driving a circulation or wash pump assembly 200 and adrain pump assembly 202. The wash pump assembly 200 and the drain pumpassembly 202 may each be coupled to the bottom portion 192 of driveshaft 176, e.g., with the wash pump assembly 200 above the drain pumpassembly 202 and below the motor 170 along the vertical direction V.Wash pump assembly 200 may generally be configured for circulating washfluid within wash chamber 106 during wash and/or rinse cycles. Drainpump assembly 202 may generally be configured for periodicallydischarging soiled wash from dishwasher 100. Each of these assemblieswill be described in more detail below.

According to an exemplary embodiment, wash pump assembly 200 may beconfigured to provide wash fluid to spray arm assemblies 140, 146, 148.More specifically, wash pump assembly 200 may include a wash pumpimpeller 210 disposed on bottom portion 192 of drive shaft 176 within apump housing 212. Pump housing 212 defines a pump intake 214 for drawingwash fluid into wash pump impeller 210. According to the illustratedembodiment, pump intake 214 is facing downward along the verticaldirection V and is located very near the bottom of sump portion 144. Inthis manner, the amount of water required to prime and operate wash pumpassembly 200 is minimized. This is particularly advantageous whenrunning low water cycles for the purpose of water and energy savings.

In operation, wash pump impeller 210 draws wash fluid in from sumpportion 144 and pumps it to a diverter assembly 220. Diverter assembly220 may include a diverter disc 222 disposed within a diverter chamber224 for selectively distributing the wash fluid to the spray armassemblies 140, 146, 148. More particularly, diverter disc 222 may berotatably mounted about the vertical direction V. Diverter disc 222 mayhave an aperture that is configured to align with one of a plurality ofoutlet ports 303, 304, 305, and 306 (FIG. 4) at the top of diverterchamber 224. When diverter disc 222 rotates about the vertical directionV, the aperture moves from alignment with one of the plurality of outletports 303, 304, 305, and 306 to alignment with a next adjacent one ofthe plurality of outlet ports 303, 304, 305, and 306.

In addition, drain pump assembly 200 may be configured for dischargingsoiled wash fluid from the dishwasher 100 periodically. Morespecifically, drain pump assembly 202 may include a drain pump impeller230 disposed on bottom portion 192 of drive shaft 176 below the washpump impeller 210 and within a drain pump volute 232. Drain pump volute232 is positioned at the very bottom of sump portion 144, such that washfluid collects within drain pump volute 232. During a drain cycle, drainpump impeller 230 is rotated and soiled wash fluid is discharged fromdishwasher 100 through a discharge conduit 234. After some or all of thesoiled wash fluid is discharged, fresh water and/or wash additives maybe added and the wash or rinse cycle may be repeated. Notably, drainpump impeller 230 is coupled to bottom portion 192 of drive shaft 176using a one-way clutch 236. In this regard, during a wash pump mode,drive motor 170 rotates in one direction, e.g., a first direction,pumping filtered wash fluid using wash pump impeller 210. However, whendrive shaft 176 rotates in the first direction, one-way clutch 236 isdisengaged, so drain pump impeller 230 does not rotate. By contrast,during a drain pump mode, drive motor 170 rotates in the oppositedirection, e.g., a second direction opposing the first direction,thereby engaging one-way clutch 236 and causing drain pump impeller 230to rotate and discharge wash fluid.

Additionally, the wash pump impeller 210 may be configured such that itis more efficient in the first direction of rotation than in the seconddirection of rotation. For example, as is generally understood in theart, the wash pump impeller 210 may include blades (not shown), and theblades may have a cross-sectional profile and may define an angle withrespect to the vertical direction V. Thus, the wash pump impeller 210may be configured such that the profile and angle of the blades make itmore efficient in the first direction of rotation than in the seconddirection of rotation. The general principles of impeller blade designare understood by those of ordinary skill in the art and are notdiscussed in greater detail herein.

As illustrated in FIG. 4, the exemplary diverter assembly 220 includes aplurality of outlet ports, e.g., the diverter assembly 220 may includefour outlet ports, including first outlet port 303, second outlet port304, third outlet port 305, and fourth outlet port 306. Diverterassembly 220 also includes a valve 300 (see, e.g., FIGS. 5 through 8),more fully described below, that can be selectively actuated, e.g., byhydraulic actuation, depending on which of the outlet ports 303, 304,305, and 306 receives the flow of wash fluid, e.g., from an aperture ofthe diverter disc 222, as described above. As shown in FIG. 4, the valve300 is configured to selectively direct the wash fluid to one or more ofa plurality of conduits 308, 310, and 312. As illustrated for example inFIG. 4 and described in more detail below, the valve 300 may provide afirst flow path A from the first outlet port 303 to the first conduit308, a second flow path B from the second outlet port 304 to the secondconduit 310, a third flow path C from the fourth outlet port 306 to thethird conduit 312, and a fourth flow path D from the third outlet port305 to both of the second conduit 310 and the third conduit 312. Forexample, first conduit 308 may be fluidly connected with a fluid-usingcomponent, e.g., for cleaning silverware. Second conduit 310 may befluidly connected with lower spray arm assembly 140. Third conduit 312may be fluidly connected with upper spray assembly 148 and mid-levelspray arm assembly 146. Other spray assemblies and connectionconfigurations may be used as well. As used herein, the terms “first,”“second,” and “third” do not necessarily denote order or sequence, e.g.,in the foregoing example embodiments, the diverter may be configured toprovide flow to the third conduit before the second conduit. As such,the rotation of diverter disc 222 may be used to selectively place pump210 in fluid communication with one or more of the spray assemblies 140,146, or 148, and/or another fluid-using component, by way of conduits308, 310, and 312, as described in an exemplary embodiment below.

As illustrated for example in FIG. 5, the valve 300 may define a housing302 and the housing 302 may be divided into a plurality of chambers by acheck valve assembly 314. For example, in some embodiments the checkvalve assembly 314 may be a dual check valve assembly which includes afirst check valve 316 and a second check valve 318. In such embodiments,the dual check valve assembly 314 may divide the housing 302 into threechambers, e.g., a first chamber 320, a second chamber 322, and a thirdchamber 324. As illustrated for example in FIG. 5, the second conduit310 may be in fluid communication with the first chamber 320 and thethird conduit 312 may be in fluid communication with the second chamber322. Also as illustrated in FIG. 5 and described in more detail below,both the second conduit 310 and the third conduit 312 may be in fluidcommunication with the third chamber 324. Further, the valve 300 mayinclude an aperture 326, and the aperture 326 may be aligned with thefirst outlet port 303 (FIG. 4) such that fluid flow from the outlet port303, along the flow path A illustrated in FIG. 4, bypasses the dualcheck valve assembly 314 and continues to the first conduit 308.

As illustrated in FIG. 5, the dual check valve assembly 314 permitsfluid flow from the third chamber 324 to the first chamber 320 and thesecond chamber 322, while preventing or limiting fluid flow from thefirst and second chambers 320 and 322 to the third chamber 324. Forexample, the first check valve 316 is configured and arranged to permitfluid flow from the third chamber 324 to the first chamber 320 whilepreventing or limiting fluid flow from the first chamber 320 to thethird chamber 324. Similarly, in the illustrated example embodiment, thesecond check valve 318 is configured and arranged to permit fluid flowfrom the third chamber 324 to the second chamber 322 while preventing orlimiting fluid flow from the second chamber 322 to the third chamber324.

For example, as illustrated in FIGS. 5-8, the valve assembly 314 mayinclude a substrate which partitions the housing 302 into the variouschambers 320, 322, and 324. The substrate may include a plurality ofapertures which generally provide fluid communication between and amongthe chambers 320, 322, and 324. The first check valve 316 and the secondcheck valve 318 may each be movably connected to the substrate, e.g., bya hinge or other flexible rotatable joint, at a respective aperture andmovable between a closed position and an open position (FIG. 8). Forexample, as described in more detail below, the second check valve 318is illustrated in the closed position in FIG. 6, the first check valve316 is illustrated in the closed position in FIG. 7, and both checkvalves 316 and 318 are depicted in the open position in FIG. 8. Asshown, the first and second check valves 316 and 318 each obstruct orclose off a respective aperture in the closed position. For example, oneor both of the substrate and the valves 316, 318 may comprise aresilient material, e.g., silicone rubber or other suitable elastomericmaterial, to provide a sealing engagement when the valves 316, 318, arein the closed position. In some exemplary embodiments, the substrate mayinclude a rigid material, e.g., a plastic material, with an elastomericmaterial, e.g., silicone rubber, overmolded onto the substrate to formgaskets at the apertures in the substrate.

FIG. 6 illustrates the valve 300 with the dual check valve assembly 314in a first position. More specifically, in FIG. 6 the first check valve316 is in a neutral or resting position where, as illustrated, the firstcheck valve 316 is slightly open in the absence of a biasing force. Thefirst position of the valve assembly 314 illustrated in FIG. 6 alsoincludes the second check valve 318 in the closed position. As may beseen from FIGS. 4 and 6, when fluid flows along flow path C, e.g., whenfluid is directed by the diverter 222 to the fourth outlet port 306(FIG. 4), the fluid will then enter the second chamber 322 (FIG. 6) andthe force of the fluid will bias the second check valve 318 to theclosed position, as illustrated in FIG. 6. Thus, flow path C continuesfrom the second chamber 322 to the third conduit 312. As such, the fluidcirculation assembly 150 may direct fluid to the upper spray assembly148 and/or mid-level spray assembly 146 when the dual check valveassembly 314 is in the first position. For example, the wash pumpassembly 200 may draw wash fluid from the sump 144 and may urge suchwash fluid through the diverter assembly 220 where, based on theposition of the diverter disc 222, the wash fluid may then be directed,e.g., through an aperture of the diverter disc 222, to the fourth outletport 306 and into the second chamber 322 of the valve 300, where thefluid will bias the second check valve 318 closed such that the fluidwill exit the valve 300 at third conduit 312.

FIG. 7 illustrates the valve 300 with the dual check valve assembly 314in a second position. More specifically, in FIG. 6 the first check valve316 is in the closed position and the second check valve 318 is in theneutral position. As may be seen from FIGS. 4 and 7, when fluid flowsalong flow path B, e.g., when fluid is directed by the diverter 222 tothe second outlet port 304 (FIG. 4), the fluid will then enter the firstchamber 320 (FIG. 7) and the force of the fluid will bias the firstcheck valve 316 to the closed position, as illustrated in FIG. 7. Thus,flow path B continues from the first chamber 320 of the valve 300 to thesecond conduit 310. As such, the fluid circulation assembly 150 maydirect fluid to the lower spray assembly 140 when the dual check valveassembly 314 is in the second position. For example, the wash pumpassembly 200 may draw wash fluid from the sump 144 and may urge suchwash fluid through the diverter assembly 220 where, based on theposition of the diverter disc 222, the wash fluid may then be directed,e.g., through an aperture of the diverter disc 222, to the second outletport 304 and into the first chamber 320 of the valve 300, where thefluid will bias the first check valve 316 closed such that the fluidwill exit the valve 300 at second conduit 310.

FIG. 8 illustrates the valve 300 with the dual check valve assembly 314in a third position, where the first check valve 316 and the secondcheck valve 318 are each in the open position. As illustrated in FIG. 8,when fluid, e.g., wash fluid from the wash pump assembly 200, flows intothe third chamber 324, e.g., from the third outlet port 305 of thediverter assembly along flow path D (FIG. 4), the fluid will bias thefirst and second check valves 316 and 318 to the open position, wherebythe fluid may flow from the third chamber 324 into the first and secondchambers 320 and 322. Thus, when the dual check valve assembly 314 is inthe third position, the fluid circulation assembly 150 may direct fluidto multiple spray assemblies, e.g., any two or all three of the sprayassemblies 140, 146, and 148.

In accordance with the foregoing, the fluid circulation assembly 150 mayadvantageously provide various flow schemes or modes. At least one ofsuch modes may be a turbo mode or multi-spray mode, which includessimultaneous operation of more than one spray assembly, such as allthree spray assemblies 140, 146, and 148. It should be noted thatadditional embodiments of the present disclosure may includesimultaneous operation of all spray assemblies in a dishwashingappliance, for example, the dishwashing appliance may have only twospray assemblies and the turbo mode may include operating both sprayassemblies. Accordingly, the turbo mode or multi-spray mode may providea reduced overall cycle time for a wash cycle of the dishwashingappliance. Moreover, the fluid circulation assembly 150 may selectivelyprovide the various flow modes without the use of a motor to actuate thediverter 222 or the dual check valve assembly 314. Omitting such motormay advantageously provide improved energy usage and reduced potentialleak points.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A dishwasher appliance defining a verticaldirection, a lateral direction, and a transverse direction that aremutually perpendicular, the dishwasher appliance comprising: a tubdefining a wash chamber for receipt of articles for washing; a lowerspray assembly located in the wash chamber and configured to direct aspray of fluid into the wash chamber; an upper spray assembly located inthe wash chamber above the lower spray assembly along the verticaldirection, the upper spray assembly configured to direct a spray offluid into the wash chamber; a sump positioned at a bottom of the washchamber for receiving fluid from the wash chamber; and a fluidcirculation assembly, the fluid circulation assembly comprising: a pumpin fluid communication with the sump, the pump configured to draw fluidfrom the sump; a diverter comprising an inlet in fluid communicationwith the pump for receiving fluid from the pump and a plurality ofoutlet ports; and a valve in fluid communication with the diverter viaone or more of the plurality of outlet ports, the valve comprising ahousing, a dual check valve assembly mounted in the housing, and aplurality of conduits, the dual check valve assembly configured toselectively direct fluid from the diverter to one or more of theplurality of conduits.
 2. The dishwasher appliance of claim 1, whereinthe dual check valve assembly defines a first chamber, a second chamber,and a third chamber within the housing of the valve.
 3. The dishwasherappliance of claim 2, wherein the dual check valve assembly permitsfluid communication from the third chamber to the first and secondchambers and limits fluid communication from the first chamber and thesecond chamber to the third chamber.
 4. The dishwasher appliance ofclaim 1, wherein the dual check valve assembly comprises a first checkvalve configured to direct fluid flow from the valve to the lower sprayassembly when the first check valve is in a closed position and a secondcheck valve configured to direct fluid flow from the valve to the upperspray assembly when the second check valve is in a closed position, andwherein the dual check valve assembly is configured to direct fluid flowto both the lower spray assembly and the upper spray assembly when thefirst check valve is in an open position and the second check valve isin an open position.
 5. The dishwasher appliance of claim 1, wherein thehousing comprises a first chamber, a second chamber, and a thirdchamber, the first chamber of the housing separated from the thirdchamber of the housing by a first check valve of the dual check valveassembly, and the second chamber of the housing separated from the thirdchamber of the housing by a second check valve of the dual check valveassembly.
 6. The dishwasher appliance of claim 5, wherein the firstcheck valve is configured to permit fluid communication from the thirdchamber to the first chamber and to limit fluid communication from thefirst chamber to the third chamber, and wherein the second check valveis configured to permit fluid communication from the third chamber tothe second chamber and to limit fluid communication from the secondchamber to the third chamber.
 7. The dishwasher appliance of claim 5,wherein the plurality of conduits of the valve comprises a first conduitin direct fluid communication with a first outlet port of the pluralityof outlet ports, a second conduit in direct fluid communication with thefirst chamber, and a third conduit in direct fluid communication withthe second chamber.
 8. The dishwasher appliance of claim 7, wherein thesecond conduit and the third conduit are selectively in fluidcommunication with the third chamber via the dual check valve assembly.9. The dishwasher appliance of claim 1, wherein the plurality of outletports of the diverter comprises a first outlet port, a second outletport, a third outlet port, and a fourth outlet port, the plurality ofconduits comprises a first conduit, a second conduit, and a thirdconduit, and wherein the valve is configured to direct fluid from thefirst outlet port to a first conduit of the valve, from the secondoutlet port to a second conduit of the valve, from the fourth outletport to a third conduit of the valve, and from the third outlet port tothe second conduit and the third conduit.
 10. A fluid circulationassembly, comprising: a pump; a diverter comprising an inlet and aplurality of outlet ports, the inlet of the diverter in fluidcommunication with the pump for receiving fluid from the pump; and avalve in fluid communication with the diverter via one or more of theplurality of outlet ports, the valve comprising a housing, a dual checkvalve assembly mounted in the housing, and a plurality of conduits, thedual check valve assembly configured to selectively direct fluid fromthe diverter to one or more of the plurality of conduits.
 11. The fluidcirculation assembly of claim 10, wherein the dual check valve assemblydefines a first chamber, a second chamber, and a third chamber withinthe housing of the valve.
 12. The fluid circulation assembly of claim11, wherein the dual check valve assembly permits fluid communicationfrom the third chamber to the first and second chambers and limits fluidcommunication from the first chamber and the second chamber to the thirdchamber.
 13. The fluid circulation assembly of claim 10, wherein thedual check valve assembly comprises a first check valve configured todirect fluid flow from the valve to a first spray assembly when thefirst check valve is in a closed position and a second check valveconfigured to direct fluid flow from the valve to a second sprayassembly when the second check valve is in a closed position, andwherein the dual check valve assembly is configured to direct fluid flowto both the first spray assembly and the second spray assembly when thefirst check valve is in an open position and the second check valve isin an open position.
 14. The fluid circulation assembly of claim 10,wherein the housing comprises a first chamber, a second chamber, and athird chamber, the first chamber of the housing separated from the thirdchamber of the housing by a first check valve of the dual check valveassembly, and the second chamber of the housing separated from the thirdchamber of the housing by a second check valve of the dual check valveassembly.
 15. The fluid circulation assembly of claim 14, wherein thefirst check valve is configured to permit fluid communication from thethird chamber to the first chamber and to limit fluid communication fromthe first chamber to the third chamber, and wherein the second checkvalve is configured to permit fluid communication from the third chamberto the second chamber and to limit fluid communication from the secondchamber to the third chamber.
 16. The fluid circulation assembly ofclaim 14, wherein the plurality of conduits of the valve comprises afirst conduit in direct fluid communication with a first outlet port ofthe plurality of outlet ports, a second conduit in direct fluidcommunication with the first chamber, and a third conduit in directfluid communication with the second chamber.
 17. The fluid circulationassembly of claim 16, wherein the second conduit and the third conduitare selectively in fluid communication with the third chamber via thedual check valve assembly.
 18. The fluid circulation assembly of claim10, wherein the plurality of outlet ports of the diverter comprises afirst outlet port, a second outlet port, a third outlet port, and afourth outlet port, the plurality of conduits comprises a first conduit,a second conduit, and a third conduit, and wherein the valve isconfigured to direct fluid from the first outlet port to a first conduitof the valve, from the second outlet port to a second conduit of thevalve, from the fourth outlet port to a third conduit of the valve, andfrom the third outlet port to the second conduit and the third conduit.